The goal of the Program Project as a whole is to study hierarchical levels of neural and cognitive processing in children with neurodevelopmental disorders to better understand the functional organization of these systems. Within this framework, the role of Project 3 will be to systematically examine the neural, psychophysiological, and information processing bases of major differences in social affective behavior in children with neurodevelopmental disorders of different nature and origin. Children with neurodevelopmental disorders often have significant impairments in social adaptation and social communication, which impact their relationships with others. The mechanisms that are implicated in these impairments are poorly understood. The populations selected include genetically based Williams syndrome (WS), behaviorally defined High Functioning Autism (HFA) and Language Impairment (LI), as well as children with Early Unilateral Focal Lesions (FL), contrasted with typically developing (TD) controls. The neurodevelopmental populations chosen include tendencies to extremes in social behavior, from those that are socially avoidant (HFA) to those that are socially driven (WS). In Aim 1, we provide a systematic characterization of sociability and temperament across populations, based on theoretical models. In Aim 2, experimental studies will evaluate autonomic indices of information processing of social vs. non-social, visual and auditory, affective stimuli. A further aim is to examine how differences in underlying sensory/perceptual processing (Project 1) and in spatial attention and working memory (Project 2) are reflected as differences in information processing in the social context. In Aim 3, we evaluate how the characteristic social-affective profiles of the populations (Aims 1, 2) relate to expressivity in social and non-social, language and non-language contexts. We will utilize new tools of investigation for quantifying social and non-social behavior as novel contributions to understanding how aspects of personality reflected in, e.g., narratives, language, and social interaction behaviors, converge with psychophysiological profiles and receptive processing capabilities (Aim 2, Projects 1, 2), and at the level of discourse (Project 4), to provide characterizations both bottom-up and top-down. In Aim 4, we examine the integrity of neural systems underlying social-affective behavior using high-resolution brain imaging across the populations, each at a significant risk for differing problems in social functioning. In these integrated studies, we pursue new lines of investigation that will elucidate long-standing theoretical and clinical issues in differing social-affective profiles of neurodevelopmentally disabled populations. The studies will make a significant contribution toward understanding the interrelationships of the social and affective components of communication and their underpinnings, elements that are central to human experience. Insights from these studies will add unique knowledge to our understanding of social development as well as contribute to better-informed treatment methods in the future.